contract DanielPaymentRouter {
 mapping(bytes32=>bool) private used;
 function pay(bytes32 intentId,IERC20 token,address payee,uint256 amount) external nonReentrant {
   bytes32 key=keccak256(abi.encode(msg.sender,intentId));
   if(used[key]) revert IntentAlreadyUsed();
   used[key]=true;
   uint256 beforeBalance=token.balanceOf(payee);
   token.safeTransferFrom(msg.sender,payee,amount);
   if(token.balanceOf(payee)-beforeBalance!=amount) revert InexactSettlement();
 }
}